A. We will characterize the genes of the D-ribose utilization pathway in Escherichia coli K12. Studies will include genetic mapping, restriction mapping, complementation and DNA sequencing. The nature of the regulation of this system will be determined. Based on the knowledge of the structural gene for the ribose binding protein, a screening procedure for conditional lethal mutants in the cell's secretory apparatus will be performed. A mutation, pr1B, which affects secretion in E. coli and which maps in the rbs region will be characterized. B. The mechanism of stimulation of E. coli catabolite-sensitive gens by indole acetic acid and other unusual effectors of CAP protein will be studied. Lac fusions will be used to determine whether the effects are at the transcription level. If so, mutants will be sought in the lac promoter which alter the response to these effectors. DNA sequence analysis of the mutants provides a test of a specific model for CAP action.